Ignition system and apparatus



p 1939- J. A. DORAN 7 2,173,828

IGNITION SYSTEM AND APPARATUS Original Filed Sept. 10, 1952 2Sheets-Sheet 1 p 1939- I J. A DORAN 2,173,828

IGNITION SYSTEM AND APPARATUS Original Filed Sept. 10, 1952 2Sheets-Sheet 2 Patented Sept. 26, 1939 UNITED STATES PATENT OFFICEApplication September 10, 1932, Serial No. 632,483 Renewed December 3,1937 Claims.

This invention relates to ignition systems, and particularly pertains toignition systems used for internal combustion engines.

The conventional battery ignition systems have I many inherentdisadvantages, due primarily to the construction and operation of theirbreaker contact points, ignition coils and spark plugs. Ordinary contactpoints usually have only a very small part of their surface inelectrical contact, so that they burn and pit at one small point, andthus set up a. serious resistance against the passage of current,particularly at starting speeds and at high speeds. When stronger coilsare employed to compensate for the losses at the breaker points, thecontacts burn proportionately faster. The conventional ignition coilsalso have several disadvantages which weaken their power and shortentheir life.

To overcome these troublesome defects in ignition systems, I provide anignition system with such improvements in the construction and operationof the component parts, as will produce the maximum spark strengthrequired, with minimum current consumption, with lessened resistance atthe breaker contacts, with elimination of burning and pitting of thecontacts, with greatly increased durability and life of coil, and withgenerally improved results in the operation and power output of theengine. To accomplish these improvements I have devised and arranged thevarious elements of my ignition system with many novel features.

Thus, I have utilized what I term a transmuter in the system, to providea periodic reversal of current through the breaker contacts. Preferably,I use a lever oscillating-at half the speed of the breaker arm to make acontact on one side while the breaker arm is open, and to make a contacton the other side when the breaker arm next opens. The current supply isconnected to two plates on the oscillating lever, one positive and theother negative; one pair of the receiving contacts is connected to thebreaker arm and the other pair to the breaker screw, so that the breakercontacts have their polarity reversed at every opening.- -The reversalof current through the breaker contacts has important advantages, ashereinafter described.

With the above and other objects and advantageous features in view, theinvention consists of a novel method of operation and assembly and anovel arrangement of parts more fully desclosed in the detaileddescription follawing, in conjunction with the accompanying drawings,and more particularly defined in the claims appended hereto.

In the drawings,

Fig. 1 is a diagrammatical view showing the general plan of the ignitioncircuit;

Fig. 2 is a view similar to Fig. 1 showing a mod ified arrangement;

Fig. 3 is a vertical section through the distributor head on the line 33of Fig. 4;

Fig. 4 is'a plan view of the distributor head with the cap removed;

Fig. 5 is a perspective view of the transmuter arm;

Fig. 6 is a perspective view of the rear plate therefor;

Fig. 7 is a perspective view of the negative plate therefor;

Fig. 8 is a perspective view of one of the fixed contact frames;

Fif. 9 is a perspective view of the distributor operating shaft showingthe breaker and transmuter cams.

Referring to the drawings, the general circuit employed in my novelignition system-is diagrammatically shown in Fig. 1, and includes a linecircuit In for supplying current to the primary of the ignition windingII, this circuit having a battery I 2 and the usual switch I3. Acondenser II is connected across the line, and a transmuter I5 isarranged to periodically reverse the current supplied to a contactbreaker i6 by alternately connecting points A to D and B to C, wherebythe primary winding receives a periodically reversed current, instead ofthe usual direct current. The secondary winding is successivelyconnected, through the distributor arm ll, with contacts I8 forconducting the high tension current to the spark plugs 19 and I9, whichare in series relation in the secondary circuit. Fig. 2 shows analternative circuit that reverses through the breaker points only, theparts beng similarly designated; this type of circuit may be preferablewhen the coil is located at a distance.

It has been determined that the usual interrupted direct current carriesparticles of metal from the negative contact face to the positivecontact face of the breaker points, eventually eating holes in thenegative contact point and building up, in irregular formation, thepositive contact point. This transfer of metal occurs when the contactsare arcing while being opened; as a result, the contact surfaces becomeso irregular and carbonized that the contact is poor and the highresistance restricts current flow. With such reduced current, the sparkis weakgrounded, plate ened and a high speed, high compression enginemisses.

Clean contacts of large surface deliver the maximum current and operatean engine at much higher speed without skipping. At high speeds, theduration of contact is such an infinitesimal period of time that it isexceedingly important to provide the best possible contact surfaces.Furthermore, the breaking of corroded contacts is not sufficientlydecisive to produce the desired powerful hot spark at each spark plug.

When the current at the breaker point is transmuted, and the polarity ofthe breaker contacts thus periodically reversed, there is no transfer ofmetal from one contact to the other, and there is no pitting or buildingup. Preferably, the current is reversed at every opening of the breakercontacts, although the transmuting mechanism may if desired be arrangedso as to reverse less frequently, and may allow the breaker contacts tomake several continuous openings with each polarity between eachreversal of current. To avoid arcing at the transmuter switch, I designthe actuating cams to open the breaker contacts While the transmutingswitch is closed, and to reverse the transmuter switch while the breakercontacts remain open.

The transmuting mechanism may be mounted in any convenient location, butI prefer to mount the mechanism inthe distributor as shown in Fig. 3 inorder to simplify the construction and the wiring connections. Thedistributor has the usual body 20 and cap 2|, the breaker and transmutermechanism being mounted on the plate 22 which is preferably made of aninsulation material such as fibre or Bakelite. The distributor shaft 23extends vertically through the body and plate, and has the usual wiper24 for distributing the high tension current to the terminal inserts 25through the spring 26 from the central termi-- nal insert 21, whichreceives high tension current from the coil. Mounted on the shaft 23 arethe breaker arm cam 28 and the transmuter cam 29; the breaker cam, asshown in Fig. 5, having lobes 30 corresponding in number to the enginecylinders, and the transmuter cam having lobes 3| numbering half thebreaker cam lobes.

Referring now to Fig. 4, the breaker arm 32 is shown formed of a fareblock 33-having a bumper projection 34 and a fulcrum bore 35 equippedwith a metal, preferably brass, bushing 36 for mounting on the pivot pin31 fastened to the distributor plate. A spring 38, preferably formed ofa non-ferrous alloy of a high copper content, is riveted to the fibreblock and its outer end under tension against a fixed post 38a. Anextension 39 is also riveted to block 33, its outer end being providedwith a contact 40 adapted to strike against the adjustable self-aliningcontact 4! mounted on the distributor plate. As shown, the bumper 34 ispressed against the lobes 3t, thus causing the breaker arm. to oscillateon movement of the breaker cam, and allow the contact 40 to strikecontact 4!, closing and opening the circuit.

The transmuter mechanism includes a fibre bar 42 having a bumperprojection 3 and a fulcrum bore 4 1 equipped with a metal bushing =15for pivoted mounting onthe pivot pin 46 fastened to the distributorplate. On the side or" bar s2 is mounted a plate 49 and lever spring dlwhich is under tension against a fixed post 13, electrically connectedto ground through strap 59 and screw *3 As battery usua ly has itsnegative terraimay he referred to as of positive polarity. The negativeplate 52 and the lever spring 51 are mounted on the opposite side of 42.,The outer end of spring 51 is under tension against a fixed post 58electrically connected to strap 6| which serves as the terminal toreceive the primary lead wire. The negative plate 52, spring 51, post58, and strap 5| are all insulated from the distributor. The two outerends 5| and of plate 49 serve to contact alternately against the springcontacts 53 and 54. The two outer ends 62 and 63 of plate 52 serve tocontact alternately against the spring contacts and 56. The springcontacts 53 and 55 are mounted in the frame '64, which is adjustable bymeans of screws 65, and the spring contacts 54 and 55 are mounted in theframe 65, which is adjustable by means of screws 61, each frame beingadjusted and secured so that the plate contacts strike the springcontacts properly at each end of their stroke.

Frame 64 is electrically connected by strap 68 to the post 3811, so thatframe 64 supplies current to the breaker arm contact 40. Frame 66 iselectrically connected by strap 69 to the adjustable bracket 10 whichcarries the self-alining contact 4|, so that frame 66 thussuppliescurrent to contact 4 I. It is obvious that when 62 contacts with55, 50 contacts with 54, delivering positive current to the contact 4|,while negative current goes to contact 40; when 5| contacts with 53, and63 wiih 55, positive current goes to 40 while negative current goes to4|.

The operation of the transmuter mechanism may now be explained. As thedistributor shaft revolves, the breaker arm bumper is pressed againstthe lobes 30, while the transmuter bumper is pressed against the lobes3|. The location of the bumpers is such as to synchronize theirmovements. While the transmuter is'in contact, the breaker arm opens;while the breaker arm remains open, the transmuter bar moves across tothe opposite contacts; while on such contact, the breaker arm opens;while the breaker arm remains open, the transmuter bar moves back to theopposite contacts, thus completing the cycle. The reference letters Aand C in Fig. 4 correspond to the reference letters A and C of Fig. 1.The contacts B, B correspond to the reference letter B, and the contactsD, D correspond to the reference character D in Fig. 4.

As explained in Fig. l, the wiring connections may be such that thecurrent is reversed through the primary of the coil. This is highlyadvantageous as it allows the coil to operate similarly to analternating current transformer. Such alternating or reversing ofcurrent tends to hasten the demagnetizing of the core after eachimpulse, so that the coil operates with efliciency at higher enginespeeds than is possible with a constant polarity.

However, if preferred, my ignition system may be wired as in Fig. 2,without changing the direction of current through the coil, to avoidexcess wiring to a remotely located coil.

Instead of using an oscillating transmuter, it may be desirable orpreferable, in certain construetions,.to use instead a of Bakelite orother insulating material, with rings thereon, carbon contacts beingmount-ed on a Wiper arm and contacting the rings. Preferably, the diskis mounted in the distributor base above the breaker arm mechanism, andthe carbon contacts are mounted on the lower face of the wiper. Or,copper segments may be mounted on a small revolving drum, with carbonbrushes engaging the segments to receive the battery current andtransmute it to reversed current.

The transmuting method prevents all pitting and burning of breakercontact surfaces. Inasmuch as one set of clean contacts with largebearing surfaces can transmit current fast enough for high speedengines, there is no need of supplying the conventional dual sets ofbreaker mechanisms. Therefore, with my transmuting mechanism, only oneset or breaker points are required. As the transmuting mechanism costsno more than a breaker set, the complete distributor costs no more thanthe ordinary dual set distributor. Thus the transmuting method producesthe above described advantages without any increase in manufacturingcosts.

While I have described a specific ignition system, it is merely given byway of example to show one embodiment of the invention, and it isobvious that many changes in the general arrangement of the parts, intheir specific form, in their size, and in their relative position, maybe made without departing from the spirit and the scope of the inventionas defined in the appended claims.

I claim:

1. In an ignition system the combination of an ignition coil, aninterrupter, a source of current; a circuit including the primary ofsaid coil, said interrupter and said source; switching means in saidcircuit operating each time said interrupter is open for alternatelyconditioning the circuit for reversal of current therethrough, wherebyeach closing of said interrupter will effeet a reversal of said current,and a spark plug system fed by energy from the secondary of said coil.

2. In an ignition system thencombination of an ignition coil, aninterrupter, a source of current; a circuit including the primary 0!said coil, said interrupter and said source, a reversing switch in saidcircuit, means operating each time said interrupter is open for openingand reversing said switch, thereby reversing the direction in whichcurrent flows through said primary and said interrupter each time theinterrupter closes, and a spark plug system fed by energy induced in thesecondary of saidcoil.

3. In a current reversing system, an ignition coil including a primarywinding, an interrupter, a reversing switch, a source of direct current;connections between said winding, said interrupter, said switch and saidsource whereby the polarity relation of said source to said winding andsaid interrupter may be alternately reversed, said switch and saidinterrupter operating in cycles each comprising a period during whichsaid interrupter is open and said switch opens and reverses, and aperiod during which said switch remains in its reversed position andsaid interrupter closesand opens, and a secondary winding and a circuitconnected thereto to deliver oscillating current to a spark plug system.

4. In an ignition system, a coil including a primary winding, aninterrupter connected in series with said winding, a source of directcurrent, and switching means connected thereto for al-- ternatelyreversing the polarity of the contacts of said interrupter, saidswitching means operating each time said interrupter contacts areopened.

5. In an ignition system, an ignition coil including a primary winding;a circuit connected thereto including an interrupter, a reversingswitch, and a source 01' current; an oscillatable bar forming the movingelement in said reversing switch, a cam for said interrupter, a secondcam for controlling the movement of said bar, a shaft forming a commonsupport for said cams, said cams being so timed relative to each otherthat while said first cam is holding the interrupter open, said secondcam shifts said bar to a reverse position, and while said first cam isclosing and opening-said interrupter said second cam is maintaining saidbar in said reverse position, a secondary winding in said coil, and aspark plug system fed by energy from said secondary winding.

JAMES A. DORAN.

